نتایج جستجو برای: keggin type structure

تعداد نتایج: 2715186  

Journal: :Inorganic chemistry 1998
Mahmoud S. Kaba In K. Song Dean C. Duncan Craig L. Hill Mark A. Barteau

Reported here are both STM images and spatially resolved tunneling spectra of four different polyoxometalate (POM) structural class members: Keggin structure, H(3)[PW(12)O(40)] (spherical); Finke-Droege (FD) structure, Na(16)[Cu(4)(H(2)O)(2)(P(2)W(15)O(56))(2)] (prolate spheroidal); Wells-Dawson (WD) structure, H(7)[P(2)Mo(17)VO(62)] (prolate spheroidal); and Pope-Jeannin-Preyssler (PJP) struct...

Journal: :Dalton transactions 2006
Xavier López Jorge A Fernández Josep M Poblet

In this paper we study the electronic structure of Lindqvist, Keggin, Dawson and Preyssler polyoxometalates (POMs) at the DFT level, particularly their LUMOs and reduction energies. Our aim was to revisit the previously reported evidence that a linear relationship exists between reduction potentials and molecular charges in Keggin anions. In this line of thought, we calculated one simple struct...

Journal: :ACS ES&T water 2021

Keggin-type aluminum-oxo polycations are effective coagulating agents for wastewater treatment. Previous work demonstrated that heteroatom substitution in ε-Al13 polycation leads to the formation of ε-GaAl12 and ε-GeAl12 can enhance removal bacteria, DOC, turbidity from wastewater. Additional hydrolysis species creates larger Al30 improves coagulation performance, but this aspect has not been e...

Journal: :Chemical communications 2007
Yang-Guang Li Li-Mei Dai Yong-Hui Wang Xin-Long Wang En-Bo Wang Zhong-Min Su Lin Xu

A new double-Keggin-ion-templated, molybdenum-oxide-based organic-inorganic hybrid compound has been hydrothermally synthesized and its electrocatalytic properties investigated.

Journal: :Molecules 2017
Karima Ighilahriz-Boubchir Baya Boutemeur-Kheddis Cherifa Rabia Malika Makhloufi-Chebli Maamar Hamdi Artur M S Silva

2-Benzoylamino-N-phenyl-benzamide derivatives (5a-h) were prepared from 2-phenyl-3,1-(4H)-benzoxazin-4-one 3 and substituted anilines 4a-h in the presence of a Keggin-type heteropolyacids series (H₃PW12O40·13H₂O; H₄SiW12O40·13H₂O; H₄SiMo12O40·13H₂O; and H₃PMo12O40·13H₂O) as catalysts without solvent and under microwave irradiation. We found that the use of H₃PW12O40·13H₂O acid coupled to microw...

Journal: :Dalton transactions 2009
Christian G Bochet Thérèse Draper Bernard Bocquet Michael T Pope Alan F Williams

The tungsten-182 Mössbauer spectra of a series of Keggin structure heteropolytungstates, [EW12O40]n- are reported. There is a very considerable variation in quadrupole coupling at the tungsten nucleus indicating considerable asymmetry in the electron distribution for the more electronegative elements E. The quadrupole coupling correlates well with the structural data, in particular with the dis...

Journal: :Chemical communications 2011
Yanfeng Bi Shangchao Du Wuping Liao

Two hybrid assemblies (3 and 4) with two kind of nanoscaled cluster units, the spherical [Co(24)(TC4A)(6)(MO(4))(8)Cl(6)](2+) cation (1 and 2) and Keggin-type [PM(12)O(40)](3-) anion (M = Mo (1/3), W (2/4)), were solvothermally prepared and characterized, in which the spherical units are constructed by six Co(4)-p-tert-butylthiacalix[4]arene (Co(4)-TC4A) SBUs linked by eight MO(4) tetrahedrons ...

Journal: :Molecules 2008
Karima Ighilahriz Baya Boutemeur Fariza Chami Cherifa Rabia Maâmar Hamdi Safouane M Hamdi

We have investigated a microwave-assisted synthesis of 4(3H)-quinazolinones by condensation of anthranilic acid, orthoesters (or formic acid) and substituted anilines,using Keggin-type heteropolyacids (H(3)PW(12)O(40).13H(2)O, H(4)SiW(12)O(40).13H(2)O,H(4)SiMo(12)O(40).13H(2)O or H(3)PMo(12)O(40).13H(2)O) as catalysts. We found that the the use of H(3)PW(12)O(40).13H(2)O acid coupled to microwa...

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